The reason cuttings rot is that over time, the oxygen level of the water drops unless it's moving or oxygen is added. Not only do plants need oxygen in order to grow roots (and, indeed everything else), but the bacteria that cause rotting thrive in low-oxygen environments.
If your cuttings frequently rot before they root, you know the mix is staying too wet. Add vermiculite or perlite to increase its air- holding capacity. Cuttings use energy to form new roots. If the cutting has leaves, most of the energy comes from photosynthesis.
Don't get the leaves wet!
Make sure no leaves are touching the water. If the plant has a crown – where leaves emerge from a central point – keep this above the waterline too. As a general rule of thumb, only stems should be submerged in the water as leaves and other parts are more susceptible to rotting.
Keep the humidity level higher than normal when caring for cuttings to prevent water loss from leaves, but take care not to go too high. If you're using a humidity dome, either get one that has a vent at the top or make sure you remove the dome once or twice a day to avoid spiking your humidity level too high.
In soggy soil, drowning roots shut down and rot, and new roots can't form. Without healthy roots to absorb and transport water, plant tips turn brown from thirst.
Another product that'll help prevent the spread of root rot is non-flavoured cinnamon. After having removed the dead roots, sprinkle a thin layer onto the healthy tissue before placing into a bed of new compost.
Hydrogen peroxide can help to control fungal growth and fungal infection, such as root rot, by preventing the growth of fungi. It can also help kill fungus and bacteria on plant roots.
Control is difficult because once symptoms are observed, damage to the stem or roots is usually severe. For small flower beds and potted plants, use a soil drench of a recommended fungicide. A fungicide could also be mixed with soil prior to planting as suggested by the manufacturer. Allow excessively wet soils to dry.
New cuttings have no leaves, but they do have roots. If the rooting hormone does not contain nitrogen, the cutting may be sprayed, dipped, or watered with Captan to help prevent rotting.
Once root rot is identified, you must determine if the plant can be saved. If the entire root system has already become mushy, it is too late to save the plant. However, if some healthy, white, firm roots exist, try to bring the plant back to good health by replanting in fresh soil with good drainage.
Step 1: Cut Off a Section of Stem
Crushing or tearing the stem may make it more difficult for the shoot to develop new roots. Keep cuttings cool and moist until you've potted them by placing the cut ends in water or stashing your cuttings in a plastic bag with a moist paper towel wrapped around them.
Controversially, I'm gonna suggest you don't water them very often. I would start with very evenly moist airy soil – water in sans cutting, and mix it round so it's not saturated at the bottom. Add your cutting, and then mist the surface thoroughly daily (trying not to get the cutting). Twice a day if it's hot or dry.
The basic principle behind applying mist to vegetative cuttings is simple. Without roots, cuttings cannot adequately replace the water lost to the environment due to evaporation and transpiration mainly. To aid them along the beginning of their life journey we must replace this water loss with water applications.
Use rooting powders.
You can increase your chances of success by using rooting products, Clark said. Many commercial products are available. These products kill fungus and bacteria to prevent the stem from rotting, and contain a growth hormone to speed the formation of roots.
Apart from being more mindful of how often and how much water you give your plants and plant roots, you can also use a mixture of 3 percent hydrogen peroxide concentration mixed in 1 quart of water once a week to encourage healthy root growth in your plants' roots or treat the spread of root rot and root decay.
If you use a higher concentration of hydrogen peroxide on the foliage of the plant you run the risk of burning it. You could burn the roots, but since it's necessary to kill the root rot-causing bacteria, it's a risk worth taking.
Baking soda has a pH of around nine, and its alkalinity will act as poison for fungi. It will eliminate it from the roots by alkalizing the soil and preventing it from developing.
Yes, coffee grounds can help prevent soil diseases… in a laboratory. Mixed into a growing mix, they have been found to control such harmful fungi as Pythium (which causes root rot) and Fusarium and Sclerotinia (vascular diseases).
Give your cuttings a quick start with the help of cinnamon powder. Pour a spoonful onto a paper towel and roll damp stem ends in the cinnamon. Plant the stems in fresh potting soil. The cinnamon will encourage the stem to produce more roots, while helping to prevent the fungus that causes damping-off disease.
By strategically sprinkling cinnamon around the edge of containers and baskets, most pests will simply leave it alone and move on. Even with its strong smell, cinnamon will not cause any harm to the plants.
Give cuttings bright light but not sun. Keep soil moist but not wet. The cuttings should root within three weeks. Admit air gradually to wean the cuttings from their humid environment, then pot singly before outdoor planting.
From stick to root development (Stages 1-3), propagators sometimes use too little water or moisture, but most often provide too much water, which leads to leaching and waterlogged propagation substrates (Fig. 1), uneven rooting and loss of cuttings due to rot (Fig. 2) or botrytis.